It is often necessary to amplify radio frequency signals for communication, radar and other applications. Radio frequencies span a large section of the electromagnetic spectrum. In this application when we refer to radio frequency signals or RF signals, unless otherwise stated, we mean the portion of the electromagnetic spectrum between 300 MHz to 300 GHz. Many techniques are available to amplify radio frequency signals to achieve a higher power. Low cost integrated circuit amplifiers are available but these amplifiers typically will not operate properly at high power levels. Some amplifier techniques include power combiners using multiple relatively low power amplifiers. This power combining of multiple amplifier components has been achieved through several different approaches. For example: resistive splitter/combiners, coupled-line, traveling-wave, and quasi-optical (2-dimensional) to name a few. A particular example of a power divider/combiner using a wide-angle microwave lens is described in U.S. Pat. No. 5,329,248 which is incorporated herein by reference. However, structures for efficiently combining the output of multiple lower-powered devices can be quite large at frequencies lower than about 10 gigahertz (GHz), due to the wavelengths involved.
What is needed is a better high-power radio frequency amplifier.